Mäntyharju has a great variety of locations to offer. Fishing in the rapids at Miekankoski or Pyhäkoski. Head to Korpijärvi for salmon or Pyhävesi for zander and pike. From Pyhävesi through Pyhäkoski lock you arrive at Lahnavesi, Miekankoski and Juolasvesi.
NB: From this link mantyharju.fi/mantyharju-in-english/ you'll find a brochure in English.